AppleTalk echo protocol (AEP)

The AppleTalkEcho Protocol (AEP) is a test protocol that is used to test the reachability of network nodes.

The AEP protocol generates data packets that are addressed to the nodes. In the type field of the header these data packets are marked as AEP packets. The AEP data packets are sent to the addressed nodes andchecked there by the Datagram Delivery Protocol( DDP). After the AEP packet is identified as such, the data packet is copied, given a new address, and sent back to the source address.

The AEP protocol is located at the transport layer above the Datagram Delivery Protocol.